Boltless Locking of BOP Bonnet

ABSTRACT

An apparatus for releasably connecting a bonnet to a body of a blowout preventer includes a latch plate that is mounted to the body of the blowout preventer. The latch plate has a plate profile on an outer surface of the latch plate. A clamping assembly extends through the bonnet and includes a clamping screw releasably secured to, and extending through the bonnet. A latch key is located at an inner end of the clamping screw, the latch key having a key profile shaped to mate with the plate profile and to resist relative movement between the latch key and the latch plate. The clamping assembly is moveable between an engaged position where the key profile mates with the plate profile, and a released position where the key profile is spaced apart from the plate profile.

BACKGROUND OF THE DISCLOSURE

1. Field of the Disclosure

The present disclosure relates in general to blowout preventers used inthe hydrocarbon industry, and in particular to securing a bonnet to ablowout preventer.

2. Description of Related Art

Well control is an important aspect of oil and gas exploration. Whendrilling a well, for example, for oil and gas exploration applications,devices must be put in place to prevent injury to personnel andequipment associated with the drilling activities. One such well controldevice is a blowout preventer or BOP, which is typically installed atthe surface or on the sea floor in deep water drilling arrangements. ABOP is generally used to seal a wellbore in order to control a “kick,”which occurs when a wellbore penetrates a geologic layer having aformation pressure substantially higher than the pressure maintained inthe wellbore.

Common types of blowout preventers include annular blowout preventersand ram-type blowout preventers. Ram-type preventers typically comprisea body and at least two oppositely disposed ram assemblies secured tothe blowout preventer body with a bonnet. The rams can be, for example,pipe rams (which, when activated, move to engage and surround drill pipeand well tools to seal the wellbore) or shear rams (which, whenactivated, move to engage and physically shear any drill pipe or welltools in the wellbore). The rams are typically located opposite of eachother and, whether pipe rams or shear rams, the rams typically sealagainst one another proximate a center of the wellbore in order tocompletely seal the wellbore.

Blowout preventers must be regularly maintained. Moreover, it is oftendesirable to replace pipe rams with shear rams, or vice versa, toprovide different well control options. Therefore, it is important thatthe blowout preventer includes bonnets that are easily removable so thatinterior components, such as the rams, may be accessed and maintained.

A traditional method of securing the bonnet with the body is by means ofbolts which normally vary from 6 to 12 bolts, depending on the size andpressure rating of the blowout preventer. In ideal conditions, the timeconsumed to remove each bonnet bolt will be around 4-5 minutes, therebyconsuming 30-45 minutes for every assembly or disassembly of the bonnetto the body.

SUMMARY OF THE DISCLOSURE

This application discloses systems and methods for releasably connectinga bonnet to a body of a blowout preventer that reduce the time requiredto remove and replace the bonnet on the body of the blowout preventer.

In an embodiment of the current disclosure, an apparatus for releasablyconnecting a bonnet to a body of a blowout preventer includes a latchplate that is mounted to the body of the blowout preventer, the latchplate having a plate profile on an outer surface of the latch plate. Aclamping assembly extends through the bonnet. The clamping assembly hasa clamping screw releasably secured to, and extending through thebonnet. The clamping assembly also includes a latch key located at aninner end of the clamping screw. The latch key has a key profile shapedto mate with the plate profile and to resist relative movement betweenthe latch key and the latch plate. The clamping assembly is moveablebetween an engaged position where the key profile mates with the plateprofile, and a released position where the key profile is spaced apartfrom the plate profile.

In an alternate embodiment of the current disclosure, a blowoutpreventer assembly with an apparatus for releasably connecting a bonnetto the blowout preventer is disclosed. The blowout preventer assemblyincludes a blowout preventer with a body. A latch plate is mounted tothe body, the latch plate having a plate profile on an outer surface ofthe latch plate. A clamping assembly extends through the bonnet. Theclamping assembly includes a clamping screw releasably secured to, andextending through the bonnet. The clamping assembly also includes alatch key located at an inner end of the clamping screw. A ram assemblyextends radially from the body and is secured to the bonnet. The latchkey has a key profile shaped to mate with the plate profile and toresist relative movement between the latch key and the latch plate in adirection along a central ram axis of the ram assembly. The clampingassembly is moveable between an engaged position where the key profilemates with the plate profile, and a released position where the keyprofile is spaced apart from the plate profile.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the features, advantages and objects of theinvention, as well as others which will become apparent, are attainedand can be understood in more detail, more particular description of theinvention briefly summarized above may be had by reference to theembodiment thereof which is illustrated in the appended drawings, whichdrawings form a part of this specification. It is to be noted, however,that the drawings illustrate only a preferred embodiment of theinvention and are therefore not to be considered limiting of its scopeas the invention may admit to other equally effective embodiments.

FIG. 1 is a perspective view of a blowout preventer with a latchingapparatus for releasably connecting a bonnet to a body of the blowoutpreventer, in accordance with an embodiment of this disclosure, shownwith a portion of the bonnet cut away to view the latching apparatus.

FIG. 2 is a detail view of a portion of a partial section perspectiveview of the blowout preventer of FIG. 1.

FIG. 3 is a top section view of the latching apparatus of FIG. 1, withthe latching apparatus in a released position.

FIG. 4 is a top section view of the latching apparatus of FIG. 1, withthe latching apparatus in an engaged position.

DETAILED DESCRIPTION OF THE DISCLOSURE

The systems and methods of the present disclosure will now be describedmore fully hereinafter with reference to the accompanying drawings whichillustrate embodiments of the invention. The system and method if thisdisclosure may, however, be embodied in many different forms and shouldnot be construed as limited to the illustrated embodiments set forthherein. Rather, these embodiments are provided so that this disclosurewill be thorough and complete, and will fully convey the scope of theinvention to those skilled in the art. Like numbers refer to likeelements throughout, and the prime notation, if used, indicates similarelements in alternative embodiments.

Referring to FIG. 1, blowout preventer 10 with latching apparatus 12 isshown. Blowout preventer 10 includes body 14 that has central bore 16that extends from a bottom end of blowout preventer body 14 to a top endof blowout preventer body 14. In the example blowout preventer 10 ofFIG. 1, there are two pairs of ram assemblies 18, for a total of fourram assemblies 18. Each ram assembly 18 extends radially from the body14 of blowout preventer 10 so that central ram axis 20 is in a directiongenerally perpendicular to central bore 16. A pair of ram assemblies 18includes two ram assemblies 18 that are located on opposite sides ofblowout preventer 10 so that the rams within each ram assembly 18 of thepair of ram assemblies 18 can extend to mate within central bore 16.

Ram assemblies 18 can be blind rams, sealing rams, shear rams, blindshear rams, pipe rams, or other known types of rams used in blowoutpreventers 10. Blowout preventer 10 can include more than one type ofram assembly 18. In alternate embodiments, blowout preventer 10 can haveonly one pair of ram assemblies 18 or can have more than two pairs ofram assemblies 18.

Each ram assembly 18 is secured to body 14 of blowout preventer 10 withbonnet 22. Each ram assembly 18 can be secured to bonnet 22 with boltsor other known connection means. Bonnet 22 is then secured to body 14 ofblowout preventer 10 with latching apparatus 12. In the exampleembodiment of FIG. 1, bonnet 22 has a front portion 24 to which the ramassembly 18 is secured. Bonnet 22 also has two side portions 26 locatedon opposite sides of front portion 24. When assembled with blowoutpreventer 10, front portion 24 will engage an outer face 28 of body 14of blowout preventer 10 and side portions 26 will extend along recessedsides 30 of body 14 of blowout preventer 10. Recessed sides 30 areregions of blowout preventer body 14 that have a narrower width W,measured perpendicular to central ram axis 20, than the width ofpreventer body 14 through central bore 16.

Turning to FIGS. 2-4, latching apparatus 12 includes latch plate 32.Latch plate 32 is mounted to body 14 of blowout preventer 10. In theexample embodiment of FIGS. 3-4, latch plate 32 is secured to blowoutpreventer body 14 with threaded members 34, such as screws, that extendthrough latch plate 32 and into blowout preventer body 14. Guide pins 36can help to align latch plate 32 with blowout preventer body 14 whilelatch plate 32 is being attached to blowout preventer body 14 withthreaded members 34. Guide pins 36 also extend through latch plate 32and into blowout preventer body 14. Looking at FIG. 2, six members areshown extending through latch plate 32 on one side of latch plate 32. Insuch an embodiment, six other members would extend through latch plate32 on the other side of plate 32 (not shown). On each side, five suchmembers can be threaded members 34 and one can be a guide pin 36 so thateach latch plate 32 has ten threaded members and two guide pins 36. Theembodiment of FIGS. 1-4 is for example only and in other embodiments, adifferent combination of the number of threaded members 34 and guidepins 36 can be used to secure latch plate 32 to blowout preventer body14. In other alternate embodiments, other means can be used forattaching latch plate 32 to blowout preventer body 14.

Latch plate 32 has plate profile 38 on an outer surface of latch plate32. The shape and purpose of plate profile 38 will be discussed below.

Looking at FIGS. 3-4, latching apparatus 12 also includes clampingassembly 40 that extends through bonnet 22. Latching apparatus 12includes clamping screw 42 and latch key 44. Clamping screw 42 extendsthrough bonnet 22 and is releasably secured to bonnet 22. In the exampleembodiment, clamping screw 42 is threaded to bonnet 22 and has aninternal bore 46. Clamping screw 42 can be a quarter turn fastener sothat clamping screw 42 can be secured to and released from bonnet 22 byrotating clamping screw 42 less than one hundred and eighty degrees, andin certain embodiments, by rotating clamping screw 42 ninety degrees. Inthe example of FIGS. 1-2, each clamping assembly 40 includes twoclamping screws 42. In alternate embodiments, one clamping screw 42 ormore than two clamping screws 42 can be used for each clamping assembly40.

In one embodiment, for each ram assembly 18, a latch plate 32 is locatedon a first side of the body 14 of the blowout preventer 10 and clampingassembly 40 extends through a first side of bonnet 22. A second latchplate 32 is located on a second side of body 14 of blowout preventer 10and a second clamping assembly 40 extends through a second side ofbonnet 22 for the same ram assembly 18. Therefore in the exampleembodiment of FIGS. 1-2, with four ram assemblies 18, there are eightlatch plates 32 and eight clamping assemblies 40 in total.

Latch key 44 is located at an inner end of clamping screw 42. Latch key44 has a key profile 48 that is shaped to mate with plate profile 38.Clamping assembly 40 is moveable between an engaged position (FIG. 4)where key profile 48 mates with plate profile 38, and a releasedposition (FIG. 3) where key profile 48 is spaced apart from plateprofile 38. Rotating clamping screw 42 in a first direction causesclamping screw 42 to travel in a direction into bonnet 22 and move keyprofile 48 into engagement with plate profile 38. Rotating clampingscrew 42 in a second direction causes clamping screw 42 to travel in adirection out of bonnet 22 and move key profile 48 out of engagementwith plate profile 38.

When key profile 48 mates with plate profile 38, the interaction of keyprofile 48 and plate profile 38 restricts relative movement betweenlatch key 44 and latch plate 32. Key profile 48 is shaped to resistrelative movement between latch key 44 and latch plate 32 in a radiallyoutward direction D when clamping assembly 40 is in the engagedposition. Radially outward direction D is parallel with central ram axis20. When clamping assembly 40 is in the released position, bonnet 22 isremovable from blowout preventer body 14 by moving bonnet 22 away fromblowout preventer body 14 in the radially outward direction D.

In the example embodiments of FIGS. 3-4, key profile 48 and plateprofile 38 are shown with generally saw tooth patterned shapes. Plateprofile 38 has longer sloped surfaces that face generally outward awayfrom central ram axis 20 and shorter slopes surfaces that face generallyopposite to radially outward direction D. Key profile 48 has longersloped surfaces that face generally inward towards central ram axis 20and shorter slopes surfaces that face generally in radially outwarddirection D. It is the interaction of the shorter sloped surfaces ofplate profile 38 and key profile 48 that resist relative movementbetween latch key 44 and latch plate 32 in a radially outward directionD when clamping assembly 40 is in the engaged position.

In the example embodiment of FIGS. 3-4, clamping assembly 40 alsoincludes lock screw 50 that releasably secures latch key 44 to clampingscrew 42. Lock screw 50 is housed within internal bore 46 of clampingscrew 42 and carried by clamping screw 42. Lock screw 50 can have an endportion 52 that threads into latch key 44. Lock screw 50 and clampingscrew 42 can be rotated relative to each other so that rotating one oflock screw 50 and clamping screw 42 will not cause the other to rotate.Lock screw 50 can have an opposite thread direction than clamping screw42 so that, as an example, turning clamping screw 42 in a clockwisedirection will cause clamping screw 42 to travel in a direction intobonnet 22, while turning lock screw 50 in a clockwise direction wouldcause lock screw 50 to travel in a direction out of latch key 44.

In an example of operation, latch plate 32 can be mounted to body 14 ofblowout preventer 10. Clamping screw 42 can be located through bonnet 22and fastened to latch key 44 by rotating lock screw 50 in a seconddirection, such as a counterclockwise direction. Bonnet 22 with ramassembly 18 can be placed on blowout preventer body 14, and clampingscrew 42 can be rotated in a first direction, such as a clockwisedirection, to move clamping assembly 40 to the engaged position wherekey profile 48 mates with plate profile 38. All of the clamping screws42 of clamping assemblies 40 that are located on either side of blowoutpreventer body 14 will be rotated a quarter turn to move the clampingassemblies 40 to the engaged position.

With clamping assembly 40 in the engaged position, the mating of keyprofile 48 with plate profile 38 will resist relative movement betweenlatch key 44 and latch plate 32 in radially outward direction D.Therefore ram assemblies 18 will remain tightly secured to blowoutpreventer body 14 even when forces between ram assemblies 18 and blowoutpreventer body 14 during operation of blowout preventer 10 would actagainst ram assemblies 18 in a radially outward direction D.

If there is a need or desire to remove bonnet 22 from blowout preventerbody 14, clamping assembly 40 can be moved to the released position byrotating each of the clamping screws 42 a quarter turn in a seconddirection, such as a counterclockwise direction, and removing bonnet 22with ram assembly 40 from blowout preventer body 14 in the radiallyoutward direction D.

The terms “vertical”, “horizontal”, “upward”, “downward”, “above”, and“below” and similar spatial relation terminology are used herein onlyfor convenience because elements of the current disclosure may beinstalled in various relative positions.

While the invention has been shown or described in only some of itsforms, it should be apparent to those skilled in the art that it is notso limited, but is susceptible to various changes without departing fromthe scope of the invention.

What is claimed is:
 1. An apparatus for releasably connecting a bonnetto a body of a blowout preventer, the apparatus comprising: a latchplate that is mounted to the body of the blowout preventer, the latchplate having a plate profile on an outer surface of the latch plate; aclamping assembly that extends through the bonnet, the clamping assemblycomprising: a clamping screw releasably secured to, and extendingthrough the bonnet; and a latch key located at an inner end of theclamping screw, the latch key having a key profile shaped to mate withthe plate profile and to resist relative movement between the latch keyand the latch plate; and wherein the clamping assembly is moveablebetween an engaged position where the key profile mates with the plateprofile, and a released position where the key profile is spaced apartfrom the plate profile.
 2. The apparatus according to claim 1, furthercomprising a lock screw releasably securing the latch key to theclamping screw.
 3. The apparatus according to claim 1, wherein the latchplate is located on a first side of the body of the blowout preventerand the clamping assembly extends through a first side of the bonnet,and wherein the apparatus further comprises a second latch plate locatedon a second side of the body of the blowout preventer and a secondclamping assembly extending through a second side of the bonnet.
 4. Theapparatus according to claim 1, wherein the clamping screw is threadedto the bonnet and has an internal bore housing a lock screw thatreleasably secures the latch key to the clamping screw.
 5. The apparatusaccording to claim 1, wherein the clamping screw is a quarter turnfastener.
 6. The apparatus according to claim 1, wherein the key profileis shaped to resist relative movement between the latch key and thelatch plate in a radially outward direction when the clamping assemblyis in the engaged position, and wherein the bonnet is removable from thebody of the blowout preventer in the radially outward direction when theclamping assembly is in the released position.
 7. A blowout preventerassembly with an apparatus for releasably connecting a bonnet to ablowout preventer, the blowout preventer assembly comprising: a blowoutpreventer with a body; a latch plate that is mounted to the body, thelatch plate having a plate profile on an outer surface of the latchplate; a clamping assembly that extends through the bonnet, the clampingassembly comprising: a clamping screw releasably secured to, andextending through the bonnet; and a latch key located at an inner end ofthe clamping screw; a ram assembly extending radially from the body andsecured to the bonnet, the latch key having a key profile shaped to matewith the plate profile and to resist relative movement between the latchkey and the latch plate in a direction along a central ram axis of theram assembly; and wherein the clamping assembly is moveable between anengaged position where the key profile mates with the plate profile, anda released position where the key profile is spaced apart from the plateprofile.
 8. The blowout preventer assembly according to claim 7, furthercomprising a lock screw releasably securing the latch key to theclamping screw, the lock screw being carried by the clamping screw. 9.The blowout preventer assembly according to claim 7, wherein the latchplate is located on a first side of the ram assembly, and wherein theapparatus further comprises a second latch plate located on a secondside of the ram assembly.
 10. The blowout preventer assembly accordingto claim 7, wherein the clamping screw is threaded to the bonnet and hasan internal bore housing a lock screw that releasably secures the latchkey to the clamping screw.
 11. The blowout preventer assembly accordingto claim 7, wherein the clamping screw is a quarter turn fastener. 12.The blowout preventer assembly according to claim 7, wherein the bonnetand the ram assembly is removable from the body in the direction alongthe central ram axis of the ram assembly when the clamping assembly isin the released position.
 13. A method for releasably connecting abonnet to a body of a blowout preventer, the method comprising: mountinga latch plate to the body of the blowout preventer, the latch platehaving a plate profile on an outer surface of the latch plate; extendinga clamping assembly through the bonnet, the clamping assembly comprisinga clamping screw releasably secured to, and extending through thebonnet, and a latch key located at an inner end of the clamping screw,the latch key having a key profile shaped to mate with the plateprofile; and moving the clamping assembly from a released position wherethe key profile is spaced apart from the plate profile to an engagedposition where the key profile mates with the plate profile and resistsrelative movement between the latch key and the latch plate.
 14. Themethod according to claim 13, further comprising releasably securing thelatch key to the clamping screw with a lock screw.
 15. The methodaccording to claim 13, further comprising locating the latch plate on afirst side of the body of the blowout preventer and extending theclamping assembly through a first side of the bonnet, and wherein themethod further comprises locating a second latch plate on a second sideof the body of the blowout preventer and extending a second clampingassembly through a second side of the bonnet.
 16. The method accordingto claim 13, further comprising threading the clamping screw to thebonnet by rotating the clamping screw in a first direction andreleasably securing the latch key to the clamping screw with a lockscrew that is housed in an internal bore of the clamping screw, byrotating the lock screw in a second direction.
 17. The method accordingto claim 13, further comprising releasably securing the clamping screwto the bonnet by rotating the clamping screw less than one hundred andeighty degrees.
 18. The method according to claim 13, wherein the keyprofile is shaped to resist relative movement between the latch key andthe latch plate in a radially outward direction when the clampingassembly is in the engaged position, the method further comprisingmoving the clamping assembly to the released position and removing thebonnet from the body of the blowout preventer in the radially outwarddirection.